Method for analyzing stress based on multi-measured bio-signals

ABSTRACT

Disclosed is a method and system for analyzing stress and managing stress by using a mobile electronic apparatus and a data management server. The method includes: generating bio-signal pattern information upon periodically receiving a bio-signal from a bio-signal measuring device connected to each of a plurality of unspecified individuals, and forming reference information for stress analysis based on received answers to each of a plurality of questions for checking a stress level; receiving bio-signal pattern information from a bio-signal measuring device connected to a specified user; and determining a stress level corresponding to the bio-signal pattern information of the specified user based on the reference information.

CROSS REFERENCE TO RELATED APPLICATIONS

This application a continued application of U.S. patent application Ser.No. 12/208,413 filed on Sep. 11, 2008, which claims the benefit of theearlier filing date, under 35 U.S.C. § 119(a), to that patentapplication entitled “Method for Analyzing Stress Based onMulti-Measured Bio-signals,” filed in the Korean Intellectual PropertyOffice on Sep. 11, 2007 and assigned Serial No. 10-2007-0092185, thecontents of which are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a method for analyzing stress in amobile environment, and more particularly to a method for measuring aCircadian rhythm Variability (CV) of bio-signals (i.e. a pattern ofbiological signals on a daily cycle) by using a mobile sensor and amobile terminal and analyzing stress by using the measured CV.

2. Description of the Related Art

Generally, stress causing a person to internally feel strain (ortension) in their physical and/or mental condition. Stress causesinconvenience in stability of the mind or living along with otherpeople, or causes physical and mental strain. Stress, accordingly,refers to an uncharacteristic response of a body caused by pressureimposing a certain burden on bodily organs, whether the pressure ispleasant one or not. A response to temporal stress caused by an externalenvironment may be a natural phenomenon, but when a bodily response tothe stress persists for a long time, mental and physical damage mayoccur. Accordingly, in order to prevent damage due to the stress fromoccurring, known methods for measuring and easing stress have been used.

A level of stress can be determined either by measuring a biologicalchange due to the stress using an apparatus for measuring a bio-signalor by an evaluation (e.g., an interview) with a medical specialist.

Further, since stress may temporarily occur due to external factors, itis desirable to measure stress considering the external factors. Inorder to analyze chronic stress, it is desirable to continuously measurechronic stress and analyze a change transition of the measured chronicstress. However, since there is a limit to the method for measuringstress, there have been many cases where stress cannot be measured witha proper consideration of the changes in the user's environment.

Meanwhile, with recent advances in electronic technology, it is possibleto measure a bio-signal by using a mobile sensor, and with the widespread of mobile communication apparatuses, many people are using mobilecommunication terminals. By using a mobile communication terminal asdescribed above, it is possible to immediately and continuously measurestress. Accordingly, there has been a requirement for a method in whicha user can easily and accurately measure a stress state by using anapparatus carried by an individual.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a method in which a user caneasily, and accurately, measure and analyze stress in a mobileenvironment including a mobile sensor and a mobile terminal.

Also, the present invention provides a stress analysis method which cancontinuously measure stress and reduce errors in measuring stress, inorder to quantitatively manage chronic stress which can be a cause of aserious disease.

In accordance with an aspect of the present invention, there is provideda method for analyzing stress, the method including the steps of 1)generating bio-signal pattern information upon periodically receiving abio-signal from a bio-signal measuring device connected to each ofunspecified individuals and receiving a answer to each of questions forchecking a stress level, and forming reference information for stressanalysis based on the bio-signal pattern information and the answer; 2)receiving bio-signal pattern information from a bio-signal measuringdevice connected to a specified user; and 3) determining a stress levelcorresponding to the bio-signal pattern information of the specifieduser based on the reference information.

The method may further include a step of displaying the determinedstress level on a display.

Also, the method may further include a step of displaying additionallyincluded information enabling reduction of a stress level in response tothe determined stress level.

Step 1) may include the sub-steps of: providing questions for checking astress level, and determining a stress level of a user upon receiving ananswer to each of the questions; generating bio-signal patterninformation upon periodically receiving a bio-signal from each of thebio-signal measuring devices; storing the bio-signal pattern informationin connection with the stress level; and forming reference informationfor stress analysis in consideration of the bio-signal patterninformation and the stress level.

Preferably, the bio-signal corresponds to a Heart Rate Variability(HRV), and is measured by a mobile sensor for sensing a heart rate and aheart rate measurement module for converting a signal received as aninput from the mobile sensor into data representing an HRV.

Preferably, the heart rate measurement module requests measurement of abio-signal at every predetermined cycle.

Preferably, the heart rate measurement module is mounted in a mobileterminal.

The bio-signal pattern information includes a maximum value or a minimumvalue of a periodically-measured HRV.

In accordance with another aspect of the present invention, there isprovided a system for managing stress by using a mobile electronicapparatus and a data management server, the system including: at leastone mobile electronic apparatus; and a stress management server, whereineach of the at least one mobile electronic apparatus includes: abio-signal measuring device for measuring a bio-signal of a user; abio-signal pattern information generation unit for combiningbio-signals, each of which is periodically received as an input from thebio-signal measuring device, and generating bio-signal patterninformation; an individual reference information generation unit foroutputting a Stress Response Inventory (SRI) questionnaire for checkinga stress level of the user, receiving an answer to each question of theSRI questionnaire, driving the bio-signal measuring device and thebio-signal pattern information generation unit, and generatingindividual reference information obtained by connecting the result ofanswering the SRI questionnaire with the pattern information of themeasured bio-signals; and a stress analysis request unit fortransmitting the pattern information of the measured bio-signals to astress management server, and requesting analysis of a stress level ofthe user. In another aspect of the invention the stress managementserver includes: a reference information management unit for receivingthe individual reference information from each of the at least onemobile electronic apparatus, and forming a DataBase (DB) of severalpieces of the individual reference information; a bio-signal patterninformation management unit for forming a DB of the bio-signal patterninformation received from each of the at least one mobile electronicapparatus; and a stress level analysis unit for receiving a request foranalysis of a stress level of the user from a specified mobileelectronic apparatus, and analyzing the stress level.

The stress management server further includes: a site operating unit formanaging data required for site operation; and a member informationmanagement unit for managing member information including identificationinformation of each of the at least one mobile electronic apparatus,identification information of a user, a site IDentification (ID), and apass word.

The bio-signal may correspond to a Heart Rate Variability (HRV), and thebio-signal measuring device may include: a mobile sensor for sensing aheart rate, and a heart rate measurement module for converting a signalreceived as an input from the mobile sensor into data representing anHRV.

Preferably, the heart rate measurement module includes an alarm forrequesting measurement of a bio-signal at predetermined cycle orinterval.

Preferably, the bio-signal pattern information includes a maximum valueor a minimum value of a periodically-measured HRV.

Each of the at least one mobile electronic apparatus may be mounted in amobile communication terminal.

Preferably, each of the at least one mobile electronic apparatusincludes a storage medium for storing multiple SRI questionnairestherein, and selectively outputs some of the multiple SRI questionnairesas the need arises.

Preferably, the stress management server includes a storage medium forstoring multiple SRI questionnaires therein, and each of the at leastone mobile electronic apparatus requests some of the multiple SRIquestionnaires stored in the stress management server as the needarises, and outputs the some of the multiple SRI questionnaires receivedin response to the request.

In accordance with further aspect of the present invention, there isprovided a system for managing stress by using a mobile electronicapparatus and a data management server, the system including: at leastone mobile terminal; a stress management server; and a user terminal,wherein each of the at least one mobile terminal includes: a bio-signalmeasuring device for measuring a bio-signal of a user; a bio-signalpattern information generation unit for combining bio-signals, each ofwhich is periodically received as an input from the bio-signal measuringdevice, and generating bio-signal pattern information; an individualreference information generation unit for outputting a Stress ResponseInventory (SRI) questionnaire for checking a stress level of the user,receiving an answer to each question of the SRI questionnaire, drivingthe bio-signal measuring device and the bio-signal pattern informationgeneration unit, and generating individual reference informationobtained by connecting the result of answering the SRI questionnairewith the pattern information of the measured bio-signals; and a stressanalysis request unit for transmitting the pattern information of themeasured bio-signals to a stress management server, and requestinganalysis of a stress level of the user, wherein the stress managementserver includes: a bio-signal pattern information management unit forreceiving the bio-signal pattern information from the outside, andforming a bio-signal pattern information data base (DB) of the receivedbio-signal pattern information; a reference information management unitfor receiving several pieces of the individual reference informationfrom the outside, and forming an individual reference information database (DB) of the several pieces of the individual reference information;a site operating unit for managing information including images, ahyperlink, and a web page used for site operation, and performing thesite operation; a member information management unit for managing memberinformation including identification information of each of the at leastone mobile terminals, identification information of a user, a memberIDentification (ID), and a pass word; and a stress information providingunit for providing stress information including a stress levelcorresponding to pattern information of bio-signals measured by themobile terminal associated with the member ID.

In another aspect of the invention, the user terminal includes: aindividual reference information management unit for transmitting theindividual reference information received from each of the at least onemobile terminals to the stress management server; a referenceinformation storage unit for receiving reference information from thestress management server, and storing the received reference informationtherein; and a stress level analysis unit for receiving a request foranalysis of a stress level of the user from a specified mobile terminal,and analyzing the stress level based on bio-signal pattern informationreceived from the specified mobile terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary features, aspects, and advantages of thepresent invention will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating a configuration of a stressmanagement system according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a configuration of a mobileterminal included in the stress management system according to anembodiment of the present invention;

FIG. 3 is a block diagram illustrating a configuration of a stressmanagement server included in the stress management system according toan embodiment of the present invention;

FIG. 4 is a graph showing a Circadian rhythm Variability (CV) with thelapse of time of bio-signal pattern information used as referenceinformation by the stress management system according to an embodimentof the present invention;

FIG. 5 is an illustrative view of a High-Frequency normalized unit(HFn.u.) used as reference information by the stress management systemaccording to an embodiment of the present invention;

FIG. 6 a block diagram illustrating a configuration of a stressmanagement system according to another embodiment of the presentinvention;

FIG. 7 is a flowchart showing a method for analyzing stress according toan embodiment of the present invention;

FIG. 8 is a flowchart showing in detail a process in step 100 of FIG. 7;and

FIG. 9 is an illustrative view of reference information stored in aDataBase (DB) to which the method for analyzing stress according to anembodiment of the present invention is applied.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention are described in detailwith reference to the accompanying drawings. Particulars found in thefollowing description of the present invention, such as specificconfiguration elements, etc., are provided to assist those skilled inthe art with a comprehensive understanding of the present invention.Also, in the following description of the present invention, a detaileddescription of known functions and configurations incorporated, herein,will be omitted when it may make the subject matter of the presentinvention rather unclear.

FIG. 1 is a block diagram illustrating a configuration of a stressmanagement system according to an embodiment of the present invention.Referring to FIG. 1, the stress management system according to anembodiment of the present invention includes multiple mobile terminals(all referred to with the same reference numeral “10”) and a stressmanagement server 50, which are connected to one another viawired/wireless communication networks.

In an embodiment of the present invention, the stress management system50 performs a function of generating reference information forming thebasis of stress analysis and a function of analyzing a stress level byusing bio-signals of users of the multiple mobile terminals 10.Accordingly, each of the multiple mobile terminal 10 is implemented inorder to operate in a mode for generating and providing individualreference information for generating the reference information and in amode for requesting the analysis of a stress level of a user of arelevant mobile terminal 10. Also, the stress management server 50 isimplemented in order to operate in a mode for combining several piecesof the individual reference information to form a DataBase (DB) of thereference information and in a mode for analyzing a stress level, asdescribed above, to provide a result of analyzing a stress level.

A mobile terminal 10 provides a user with an interface through which theuser of the mobile terminal 10 can select either of the two modes asdescribed above (i.e. a mode for generating and providing individualreference information and a mode for requesting the analysis of a stresslevel of a user). For example, the mobile terminal 10 displays icons orcharacters respectively representing the two modes on an initial screenof a display (not shown) thereof, and receives user's input of eachdirection key (i.e. each arrow key) or each number key (not shown), sothat a mode of the mobile terminal 10 can be selected from the two modesby the user's input. When the mobile terminal 10 is set to the mode forgenerating and providing individual reference information by the user'sselection, the mobile terminal 10 provides questions for checking astress level of the user and multiple answer choices on each questionthrough the display thereof, and receives as input the selection of atleast one answer choice in response to each question. Also, the mobileterminal 10 receives as an input a bio-signal of the user as a useranswering the questions, and analyzes a pattern of the receivedbio-signals to generate bio-signal pattern information. Further, themobile terminal 10 combines the answers to the questions with thebio-signal pattern information to generate individual referenceinformation, and transmits the generated individual referenceinformation to the stress management server 50.

On the other hand, when the mobile terminal 10 is set to the mode forrequesting the analysis of a stress level by the user's selection, themobile terminal 10 receives as input a bio-signal of the user atpredetermined intervals, and analyzes a pattern of the receivedbio-signals to generate bio-signal pattern information.

A function of the stress management server 50 is based on informationtransmitted by the mobile terminal 10. Namely, upon receiving anidentifier for requesting the generation of reference information alongwith the individual reference information from the mobile terminal 10,the stress management server 50 stores the received individual referenceinformation in a data base (DB) thereof in consideration ofpredetermined rules. Also, upon receiving an identifier for requestingthe analysis of a stress level along with the bio-signal patterninformation from the mobile terminal 10, the stress management server 50checks the reference information stored in the data base (DB), searchesfor a stress level corresponding to the bio-signal pattern information,and transmits a result of the search back to the mobile terminal 10.

FIG. 2 is a block diagram illustrating a configuration of a mobileterminal 10 included in the stress management system according to anembodiment of the present invention. It can be noted from FIG. 2 thatthe mobile terminal 10, according to an embodiment of the presentinvention, can be applied to each of various apparatuses capable ofhaving the functions as described above. Nevertheless, in an embodimentof the present invention, by citing a mobile communication terminal asan example of the mobile terminal 10, hardware apparatuses forming thebasis, to which the present invention can be applied, will be describedreferring to the accompanying drawings.

Referring to FIG. 2, the mobile communication terminal included in thestress management system according to an embodiment of the presentinvention includes a bio-signal measurement module 11, a bio-signalpattern information generation unit 15, a Stress Response Inventory(SRI) measurement unit 16, an individual reference informationgeneration unit 17, a control unit 21, a memory unit 22, a display unit23, a key input unit 24, a Radio Frequency (RF) unit 25, and an RF dataprocessing unit 26.

The bio-signal measurement module 11 is implemented so that a user canfreely measure a bio-signal of the user by using a measuring devicewhich can be carried by the user. For example, when a bio-signalintended to be measured is a heart rate of the user, the bio-signalmeasurement module 11 is attached to a part of the user's body to detecta heart rate of the user, and may include a mobile heart rate sensor 12implemented in order to be able to carried by the user and a heart rateanalysis device 13 for converting a signal provided by the mobile heartrate sensor 12 into standardized data.

The bio-signal pattern information generation unit 15 combines thebio-signals provided by the bio-signal measurement module 11, andgenerates bio-signal pattern information. The bio-signal patterninformation is generated by using a bio-signal received as input atpredetermined intervals. For example, bio-signal pattern information maycorrespond to information representing a pattern obtained by measuring aheart rate signal at least one time for each of five predeterminedperiods (i.e. from 9 to 12 o'clock, from 12 to 15 o'clock, from 15 to 18o'clock, from 18 to 21 o'clock, and from 21 to 24 o'clock) and combiningthe measurement results, or the measurements may be made at a later ofonce per hour, for example, and the measurements combined every 4 hours,for example. In this illustrative case, the hourly measurements may becombined as groups with a combining time window (e.g., every 4 hours),or may be combined using a sliding window of a known time (e.g., every 4hours). Although an example of the periods are described herein, it willunderstood by those skilled in the art that the period of measurementand the period of combining may be altered without undueexperimentation.

The bio-signal pattern information generation unit 15 may include analarm for informing the user that he/she can recognize the input of abio-signal at every predetermined period. For example, when setting fivepredetermined periods (i.e. a first period from 9 to 12 o'clock (9 am-12pm), a second period from 12 to 15 o'clock (12 pm-3 pm), a third periodfrom 15 to 18 o'clock (3 pm-6 pm), a fourth period from 18 to 21 o'clock(6 pm-9 pm), and a fifth period from 21 to 24 o'clock (9 pm-midnight)),the alarm can be set so as to repeatedly give the user a warning as abio-signal is measured at predetermined time intervals (e.g. at10-minute intervals) is during any of the five predetermined periods.Even though the number of the predetermined periods is set to five in anembodiment of the present invention as described above, the presentinvention is not limited to this single configuration. The predeterminedperiods can be freely set by the user. To this end, the mobilecommunication terminal can be implemented so that the user can setpredetermined periods by selecting a menu named “bio-signal patterninformation setting” among menu items prepared for various functionsettings. Also, it goes without saying that predetermined periods may befixed in order to have values properly set by a developer and the fixedpredetermined periods can be provided to users.

The SRI measurement unit 16 displays, through the display unit 23, anSRI questionnaire selected from among multiple SRI questionnaires storedin the memory unit, and receives as input an answer or response to eachquestion of the selected SRI questionnaire through the key input unit 24and stores the responses to the selected SRI questionnaire in the memoryunit 22.

The bio-signal pattern information generation unit 15 and the SRImeasurement unit 16 are driven by a request of the individual referenceinformation generation unit 17. The individual reference informationgeneration unit 17 can be executed during the selection of a menu named“individual reference information generation” among a plurality of menuitems included in the mobile communication terminal. At this time, theindividual reference information generation unit 17 matches thebio-signal pattern information with the results from answering the SRIquestionnaire, and generates individual reference information, where thebio-signal pattern information and the answer result are stored in thememory unit 22 during the operations of the bio-signal patterninformation generation unit 15 and the SRI measurement unit 16.

The control unit 21 generally controls operations of the functionalunits by performing a function of controlling an overall operation ofthe mobile communication terminal. Namely, the control unit 21 controlsthe key input unit 24 so as to perform processing according to adetected input (e.g., a number) and a menu selection signal received asinput through the key input unit 24, controls the bio-signal measurementmodule 11 so as to process a signal received as input through thebio-signal measurement module 11, controls the memory unit 22 so as tostore the measured bio-signals and the obtained SRI information, andcontrols the bio-signal pattern information generation unit 15 and theindividual reference information generation unit 17 so as to generatebio-signal pattern information and individual reference information byusing the stored bio-signals and SRI information. Also, the control unit21 controls the display unit 23 so as to display an SRI questionnairefor obtaining the SRI information, the generated bio-signal patterninformation and individual reference information, etc. At this time, asthe need arises, the control unit 21 controls the memory unit 22 so asto provide contents stored in the memory unit 22 which are to be output,or so as to store the contents. Also, the memory unit 22 stores thereinmultiple programs and multiple pieces of data related to the operationof the control unit 21.

In addition, upon receiving as input the selection of a menu named“stress level check” among the menu items included in the mobilecommunication terminal, the control unit 21 transmits the bio-signalsand the bio-signal pattern information stored in the memory unit 22 tothe stress management server 50, and requests stress analysis along withthe transmission. When receiving a result of the stress analysis, thecontrol unit 21 controls the memory unit 22 so as to store the result ofthe stress analysis, and controls the display unit 24 to display theresult of the stress analysis so that the user can check the result ofthe stress analysis. Further, upon receiving a request for checking astress level from the user, the control unit 21 controls the bio-signalpattern information generation unit 15 so as to operate in real time andgenerate bio-signal pattern information. When the bio-signal patterninformation is generated, the control unit 21 transmits the bio-signalpattern information to a user terminal 30, and requests stress analysisalong with the transmission. When receiving the result of the stressanalysis, the control unit 21 controls the memory unit 22 so as to storethe result of the stress analysis, and controls the display unit 24 soas to display and provide the result of the stress analysis.

The display unit 23 may be implemented by using a display device, suchas a Liquid Crystal Display (LCD), etc., and displays not only messagesindicating various operation states of the relevant terminal, but alsophotographed digital image data, under the control of the control unit21. The key input unit 24 receives as input a telephone number or acharacter from the user, for example. To this end, the key input unit 24includes keys for inputting numerals and characters and function keysfor setting various functions, and outputs an input signal through eachkey to the control unit 21.

The RF unit 25 modulates voice data, character data, and control data ofthe user into an RF signal, and transmits the RF signal to a basestation (not shown) of a mobile communication network. When receiving anRF signal from the base station, the RF unit 25 demodulates the receivedRF signal into voice data, character data, control data, etc., andoutputs the data. Under the control of the control unit 21, the RF dataprocessing unit 26 decodes voice data received by the RF unit 25, andoutputs the decoded voice data as an audible sound through a speaker.Also, the RF data processing unit 26 converts a voice signal of the userreceived as input from a microphone into data and outputs the converteddata to the RF unit 25, and provides character data and control datareceived as input through the RF unit 25 to the control unit 21.

The mobile terminal having the configuration as described above performsan operation related to a conventional mobile communication service. Atthis time, besides the functions as described above, the control unit 21performs both a function of generating individual reference informationand a function of checking a stress level based on bio-signals of theuser, according to the features of the present invention.

FIG. 3 is a block diagram illustrating a configuration of the stressmanagement server 50 included in the stress management system accordingto an embodiment of the present invention. Referring to FIG. 3, thestress management server 50 according to an embodiment of the presentinvention includes a communication interface 51, a control unit 52, areference information management unit 53, a stress analysis unit 54, anda reference information data base (DB) 61.

The communication interface 51 acts as an interface for transmittingdata between the mobile terminal 10 and the stress management server 50,and can be implemented by using one of a plurality of known interfacescapable of transmitting data over wired/wireless communication networks.

The control unit 52 generally controls operations of the functionalunits by performing a function of controlling an overall operation ofthe stress management server 50. Namely, the control unit 52 checks datareceived via the communication interface 51, and directs operations ofthe reference information management unit 53 and the stress analysisunit 54, etc., according to commands included in the received data.

In consideration of a stress level and a result of answering an SRIquestionnaire, the reference information management unit 53 storesindividual reference information received from a mobile terminal 10 inthe reference information DB 61, and manages the individual referenceinformation.

Since various mental processes appear as dynamic changes of heartbeatintervals (i.e. RR intervals) through control of an autonomic nervoussystem, the analysis of a Heart Rate Variability (HRV) makes it possibleto analyze a stress level. Particularly, a group suffering from chronicstress is hindered in a control action of the autonomic nervous systemdue to increased hormones, and therefore, has a slower HRV and undergoesa more frequently-occurring circadian rhythm of hormone production (i.e.a change of hormone production on a daily cycle) than normal people.Accordingly, with data on heartbeat intervals of normal people asreference, statistical analysis for each age group is performed on aratio between low and high frequency components (an LF/HF ratio) fromamong parameters of an HRV and official values obtained from a heightand a width of a histogram of the value of an HRV, so that it ispossible to calculate a stress level.

Accordingly, in an embodiment of the present invention, a bio-signal maycorrespond to a signal obtained by measuring a heart rate, andbio-signal pattern information may include the value of measuring aheart rate for each period.

Also, the reference information management unit 53 classifies peopleanswering their own SRI questionnaires into a high stress group and alow stress group based on the responses to each SRI questionnaire, andforms a reference of a stress level based on bio-signals received asinput from subjects belonging to each group. For example, as in FIG. 4,the reference information management unit 53 performs curve fitting on aCircadian rhythm Variability (CV) of the bio-signal pattern information(i.e. a pattern of the bio-signal pattern information on a daily cycle)in order to find an equation (e.g., a quadratic or other higher orderpolynomial equation), thereby setting a reference of each group. Also,the reference information management unit 53 measures an HFn.u. as inFIG. 5, thereby setting a reference of each group.

Upon receiving a request for stress analysis from the mobile terminal10, the stress analysis unit 54 analyzes stress based on the bio-signalsand bio-signal pattern information. Specifically, the stress analysisunit 54 performs curve fitting on the bio-signal pattern information inorder to find, for example, a quadratic equation, and defines a timepoint with an effective value (e.g. p<0.05) as a reference of thebio-signal pattern information. Also, the stress analysis unit 54compares a variability of pattern information of input bio-signals withthe reference of the bio-signal pattern information by using an F-test,and specify a change of the bio-signal pattern information for eachdate. Also, the stress analysis unit 54 compares an average of patterninformation of bio-signals, which are measured and then received asinput, with the reference of the bio-signal pattern information, anddetermines if a stress level is increased or decreased.

Meanwhile, the reference information data base DB 61 is used to classifyand store information on a response to each SRI questionnaire, a stresslevel corresponding to response(s), the age and sex distinction of eachuser answering their own SRI questionnaire, etc., and individualreference information including bio-signal pattern information of eachuser, where several pieces of the information are managed in connectionwith one another. Accordingly, the stress analysis unit 54 can check astress level corresponding to the bio-signal pattern information withreference to the reference information DB 61. Namely, when receiving arequest for stress analysis along with the reception of the bio-signalpattern information from the mobile terminal 10, the stress analysisunit 54 checks the reference information DB 61, and extracts individualreference information corresponding to the bio-signal patterninformation from the information stored in the reference information DB61. Then, the stress analysis unit 54 checks a stress level included inthe extracted individual reference information.

Also, the stress management server 50 can provide information related tostress through a web site. To this end, the stress management server 50may further include a site operating unit 55, an operation informationdata base DB 62, a member information data base DB 66, and a bio-signalpattern information data base DB 67.

Herein, the site operating unit 55 operates a site according to analgorithm for driving a web site. The operation information data base DB62 stores therein various data required for the site operation (e.g.operation information including a web page, images, a hyperlink, etc.).The member information data base DB 66 stores IDentification (ID) of amember subscribing to a site, an identification code of a user terminalof each member, etc. The bio-signal pattern information data base DB 67stores bio-signal pattern information received from a mobile terminal 10of each member.

FIG. 6 a block diagram illustrating a configuration of a stressmanagement system according to another embodiment of the presentinvention. Referring to FIG. 6, the stress management system accordingto another embodiment of the present invention may further include auser terminal 30 as a configuration apparatus for mediating between amobile terminal 10 and the stress management server 50 according to anembodiment of the present invention.

The user terminal 30 may be implemented by using a conventional PersonalComputer (PC) loaded with a stress management program. The user terminal30 can be implemented in order to perform the function of the stressanalysis unit 54 of the stress management server 50 according to anembodiment of the present invention. Also, upon receiving, as the needarises, information stored in the reference information data base DB 61from the stress management server 50, the user terminal 30 can store andmanage the received information. Since the user terminal 30 performs thestress analysis function, the stress management server 50 does not needto include the stress analysis unit 54.

In another aspect, the stress management server 50 can provide not onlya stress level corresponding to a measured bio-signal, but also variousmethods for relieving stress in response to the stress level. Forexample, the stress management server 50 can receive a treatmentcorresponding to a stress level, etc., from a user with expertise onstress (e.g. a psychiatrist), and provide the received treatment.

A detailed description of a method for analyzing stress according to thepresent invention with reference to the accompanying drawings.

FIG. 7 is a flowchart showing a method for analyzing stress according toan embodiment of the present invention, and FIG. 8 is a flowchartshowing in detail a process shown in step 100 of FIG. 7. Referring toFIGS. 7 and 8, in the method for analyzing stress according to anembodiment of the present invention, before performing stress analysis,reference information is generated in order to discriminate between anormal group and a stress group during the stress analysis (step 100).

Preferably, step 100 is performed by learning both a result of answeringquestions included in an SRI questionnaire and a bio-signal which arereceived as input from each of unspecified individuals, and may includesteps 110 to 200 (refer to FIG. 8). First, step 110 is performed byselecting a menu for generating reference information among menu itemsincluded in a mobile phone by a user. For example, when the menu forgenerating reference information is a menu named “generation ofindividual reference information,” step 110 is performed by selectingthe menu named “generation of individual reference information” by theuser. When the menu named “generation of individual referenceinformation” is selected, the mobile terminal first receives as inputuser characteristics, such as age, sex, etc., of the user, and selectsan SRI questionnaire corresponding to the input characteristic, (e.g.,age, sex, etc.), among all SRI questionnaires stored in the memory unit.Then, the mobile terminal displays the selected SRI questionnaire,including multiple SRI questions and multiple answer choices on each ofthe multiple SRI questions, on a screen (step 120), receives as an inputresponses to the displayed SRI questionnaire (step 130), and stores theinput responses (step 140). Steps 120, 130, and 140 are repeatedlyperformed until an answer to each of the selected SRI questions isreceived (or until the user indicates that enough responses have beenprovided). When an answer to each of the selected SRI questions iscompleted, the mobile terminal measures a bio-signal of the useranswering the selected SRI questionnaire. A bio-signal is measured inconsideration of a CV in order to check a change of a bio-signal on a24-hour cycle. For example, a daily cycle can be divided into a firstperiod from 9 to 12 o'clock, a second period from 12 to 15 o'clock, athird period from 15 to 18 o'clock, a fourth period from 18 to 21o'clock, and a fifth period from 21 to 24 o'clock. Then, a bio-signal ofthe user answering the SRI questionnaire is measured at least one timeduring each period. Namely, if the performance of step 140 is completed,by performing step 150, a period corresponding to a completed time pointis checked, and at least one bio-signal is measured at least one timeduring the period. Then, until reaching the next period, the measurementof a bio-signal is in a waiting state (step 160). When reaching the nextperiod, a bio-signal is again measured (step 170). Steps 160 and 170 arerepeatedly performed until a bio-signal is measured at least one timefor each of the first through fifth periods. Herein, through the mobileterminal, the user can set either of two parameters: the number of timesof measuring a bio-signal in each period (e.g. a bio-signal is measuredthree times in each period for 24 hours from a time point of completingthe performance of step 140), and the number of times of measuring abio-signal at every daily cycle (e.g. a bio-signal is measured for threedays in such a condition that the bio-signal is measured once duringeach period).

Further, the present invention does not limit the number of times ofmeasuring a bio-signal, and the number of times of measuring abio-signal may be determined according to an algorithm for generatingreference information forming the basis of stress analysis. Next, if themeasurement of a bio-signal during a daily cycle is completed, step 180is performed. In step 180, bio-signal pattern information is generated,which includes a pattern of bio-signals measured during a daily cycle.For example, curve fitting is performed on bio-signals measured during adaily period in order to find a quadratic equation, for example,effective points are determined among points on which the curve fittingis performed, and a pattern formed by the effective points is generatedas the bio-signal pattern information. Then, individual referenceinformation is generated which is obtained by connecting the bio-signalpattern information with the result of answering the SRI questionnaire(step 190). The generated individual reference information can beprovided to the stress management server, and several pieces ofindividual reference information as provided above are stored in thestress management server. Finally, the stress management server combinesseveral pieces of individual reference information respectively providedby multiple users, and generates several pieces of reference informationclassified according to predetermined criteria (e.g. a stress levelaccording to sex and/or each age) (step 200). Step 100 can becontinuously and repeatedly performed by a request of a user of a mobileterminal, and the reference information can be continuously updatedthrough learning. Further, as individual reference information from eachof many and unspecified users is continuously updated, more pieces ofbio-signal pattern information of users belonging to each of variousgroups and more various samples can be secured. Accordingly, stress canbe more accurately analyzed.

Step 200 is performed by selecting a menu for requesting stress analysis(e.g. a menu named “stress analysis”) among menu items included in themobile terminal by the user.

Specifically, upon receiving as input the selection of the menu forstress analysis from the user, the mobile terminal measures a bio-signalof the user, and generates bio-signal pattern information. A process formeasuring a bio-signal and a process for generating bio-signal patterninformation are achieved through the same process as a process forperforming steps 150, 160, 170, and 180 as described above. When thebio-signal pattern information is generated as described above, thebio-signal pattern information is transmitted to an apparatus (e.g. thestress management server) for analyzing a stress level by using thereference information, and requests the apparatus to analyze stress.

Even though the mobile terminal receives as input the selection of amenu for stress analysis from the user and generates bio-signal patterninformation in an embodiment of the present invention, the presentinvention is not limited to this. For example, a user may previouslymeasure his/her own bio-signals, generate pattern information of themeasured bio-signals, and then store the generated bio-signal patterninformation in a mobile terminal of the user. Then, as the need arises,the user may select the stored bio-signal pattern information, andrequest stress analysis.

Next, the apparatus (e.g. the stress management server or user terminal30, FIG. 6) for analyzing a stress level receives the bio-signal patterninformation, and checks a stress level corresponding to the receivedbio-signal pattern information (step 500). Specifically, the apparatuschecks a polynomial equation of known order (e.g., quadratic is of order2) of bio-signal pattern information of a group corresponding to the sexor age of the user whose bio-signal has been measured within thereference information, and extracts individual reference informationhaving bio-signal pattern information similar in form to, for example, aquadratic equation of the pattern information of the measuredbio-signals. Then, the apparatus checks a result of answering an SRIquestionnaire included in the extracted individual referenceinformation, checks a stress level based on the answer result, and thendetermines the checked stress level as a stress level of the user.

FIG. 9 is an illustrative view of reference information stored in a database DB to which the method for analyzing stress according to anembodiment of the present invention is applied. Referring to FIG. 9, asan example, it is assumed that sex and age received as input from a userrequesting stress measurement are respectively the male sex and “31,”and a quadratic equation of pattern information of measured bio-signalsis “X²+X+3.” Since the quadratic equation of the pattern information ofthe measured bio-signals is similar to a quadratic equation ofbio-signal pattern information of an identification number “130002”within the reference information, the identification number “130002” isextracted as individual reference information. Then, a stress level ofthe extracted individual reference information is checked.

The checked stress level is transmitted back to the mobile terminal, andthe mobile terminal displays the result (e.g. the checked stress level)transmitted back thereto on a screen thereof (step 700).

In the method for analyzing stress according to the present invention,the stress management server receives individual reference informationprovided by each of the multiple mobile terminals, generates and updatesreference information by using the several pieces of individualreference information, analyzes stress by using the updated referenceinformation, and then provides a result of analyzing stress.Nevertheless, the present invention is not limited to this, and it goeswithout saying that various methods for analyzing stress can beperformed by a system including the multiple mobile terminals and thestress management server, etc. For example, the stress management servermay perform only the function of receiving individual referenceinformation provided by each of the multiple mobile terminals,generating reference information, and providing the generated referenceinformation to a user terminal (e.g. a conventional personal computer).On the other hand, the user terminal may store, in a separate memory,reference information stored in the stress management server, continueto update the reference information, and analyze stress by using thereference information and a stress analysis tool stored in the userterminal.

The above-described methods according to the present invention can berealized in hardware or via the execution of software or computer codethat can be stored in a recording medium such as a CD ROM, an RAM, afloppy disk, a hard disk, or a magneto-optical disk or downloaded over anetwork, so that the methods described herein can be executed by suchsoftware using a general purpose computer, or a special processor or inprogrammable or dedicated hardware, such as an ASIC or FPGA. As would beunderstood in the art, the computer, the processor or the programmablehardware include memory components, e.g., RAM, ROM, Flash, etc. that maystore or receive software or computer code that when accessed andexecuted by the computer, processor or hardware implement the processingmethods described herein.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention.Therefore, the spirit and scope of the present invention must be definednot by described embodiments thereof but by the appended claims andequivalents of the appended claims.

What is claimed is:
 1. A method for analyzing stress, the methodcomprising the steps of: periodically measuring one or more bio-signalsof a user; displaying on a display device an interface with a firstobject and a second object; operating a controller, in a first mode forgenerating and providing individual reference information, when thefirst object is selected, wherein the first mode comprises: generatingbio-signal pattern information based on the one or more bio-signals;providing a set of questions for checking an unknown stress level, andreceiving one or more answers to each of the questions; and forming theindividual reference information based on the bio-signal patterninformation and the one or more answers at a database (DB) server;operating the controller in a second mode for requesting analysis of thestress level when the second object is selected, wherein the secondcomprises: transmitting, to a management server, the one or morebio-signals and a request for analyzing the stress level of the userbased on the individual reference information, wherein the managementserver includes the DB server storing a plurality of bio-signalpatterns; when the stress level of the user is determined by the DBserver, receiving information for the stress level of the user from themanagement server, wherein the stress level is determined based on adetermination of a particular one of the plurality of bio-signal patternthat is most similar to the one or more bio-signal; and displayinginformation related to the stress level of the user, based on theindividual reference information.
 2. The method of claim 1, whereindisplaying the information related to the stress level of the usercomprises: displaying the stress level on the display device.
 3. Themethod of claim 2, further comprising: displaying additionally includedinformation enabling reduction of the stress level on the displaydevice.
 4. The method of claim 1, wherein the one or more bio-signalsinclude a Heart Rate Variability (HRV), and are measured by a mobilesensor for sensing a heart rate or a heart rate measurement module forconverting a signal received as an input from the mobile sensor intodata representing an HRV.
 5. The method of claim 4, wherein the heartrate measurement module requests measurement of a bio-signal atpredetermined cycles.
 6. The method of claim 4, wherein the heart ratemeasurement module is mounted in a mobile terminal.
 7. The method ofclaim 4, wherein the bio-signal pattern information includes a maximumvalue or a minimum value of a periodically-measured HRV.
 8. A mobileterminal for managing stress, the mobile terminal comprising: acommunication interface; one or more sensors configured to periodicallymeasure one or more bio-signals of a user; a display device configuredto display an interface comprising a first object and a second object; acontroller, when the first object is selected, configured to operate ina first mode for generating and providing individual referenceinformation, wherein the controller: generates bio-signal patterninformation based on the one or more bio-signals, outputs a StressResponse Inventory (SRI) questionnaire for checking an unknown stresslevel of the user, receives one or more answers to each question of theSRI questionnaire, and generates individual reference informationobtained by correlating results of answering the SRI questionnaire withthe bio-signal pattern information at a database (DB) server, andwherein the controller, when the second object is selected, isconfigured to operating in a second mode for requesting analysis of thestress level, wherein the controller: controls the communicationinterface to transmit, to a management server, the one or morebio-signals and a request for analyzing the stress level of the user,based on the reference information, wherein the management serverincludes the DB server storing a plurality of bio-signal patterns, andwhen the stress level of the user is determined by the DB server,controls the communication interface to receive information related tothe stress level for the user from the management server, wherein thestress level is determined based on a determination of a particular oneof the plurality of bio-signal pattern that is most similar to the oneor more bio-signal; and wherein the display device is further configuredto display information related to the stress level of the user, based onthe individual reference information.
 9. The mobile terminal of claim 8,wherein the controller is further configured to combine the one or morebio-signals to generate the bio-signal pattern information.
 10. Themobile terminal of claim 9, wherein the one or more bio-signals includea Heart Rate Variability (HRV).
 11. The mobile terminal of claim 10,wherein the one or more sensors comprises: a mobile sensor for sensing aheart rate; and a heart rate measurement module for converting a signalreceived as an input from the mobile sensor into data representing anHRV.
 12. The mobile terminal of claim 11, wherein the heart ratemeasurement module alarms the request for measuring a bio-signal atpredetermined cycles.
 13. The mobile terminal of claim 11, wherein eachof a mobile sensor and the heart rate measurement module is mounted inthe mobile terminal.
 14. The mobile terminal of claim 10, wherein thebio-signal pattern information includes a maximum value or a minimumvalue of a periodically-measured HRV.
 15. The mobile terminal of claim8, further comprising: a memory configured to store multiple SRIquestionnaire, wherein some of the multiple SRI questionnaires areselectively outputted.
 16. The mobile terminal of claim 8, wherein thereference information is associated with an identification of the userand transmitting the request further comprises transmitting a requestcomprising the identifier of the user.